1. Field of the Invention
The present invention relates to a disc brake for a vehicle that is used in vehicles such as automobiles and motorcycles. More specifically, the invention relates to the structure of pad retainers that are set in pad guide grooves of caliper support arms and movably support ears of back plates of friction pads.
2. Description of the Related Art
In general, in conventional disc brakes in which friction pads are hung and held so as to be movable in the disc axial direction in such a manner that ears projecting from both side portions of back plates of the friction pads are movably supported by pad guide grooves that are formed in caliper support arms of a caliper bracket, pad retainers made of a metal thin plate are interposed between the pad guide grooves and the ears. Each pad retainer is formed with pad returning mechanisms that are brought in contact with the disc-rotor-entrance-side and exit-side side faces of the ears and urge the ears parallel with the disc axial direction away from the disc rotor. In a non-braking state, the pad returning mechanisms (pad springing-back portions) forcibly return the friction pads from the disc rotor, whereby dragging of the friction pads and juddering that is caused by wear of the disc rotor are prevented and brake noise is reduced (refer to JP-UM-A-56-129624, for example).
However, with the above configuration in which the pad returning mechanisms urge the friction pads away from the disc rotor, in tentatively attaching the friction pads to the pad guide grooves of the caliper support arms, the friction pads are pushed away from the disc rotor and may fall off the caliper support arms. As a result, the attachment work takes much time.
Although as described above the pad retainers having the above structure have the effect of returning the friction pads from the disc rotor in a non-braking state, they cannot prevent the ears from playing in the disc radial direction inside the pad guide grooves. Further, since the friction pads are always urged away from the disc rotor by the pad springing-back portions, the friction pads are prone to fall off a caliper bracket in attaching the friction pads to the caliper bracket tentatively. The attachment work thus takes much time.